Back to the Future is a 1985 American science fiction film, which stars Michael J. Fox as teenager Marty McFly, who accidentally travels back in time to 1955, where he meets his future parents and becomes his mother's romantic interest. Christopher … more »

Marty: You're alive! Bulletproof vest? How did you know? I di-I never got a chance to tell you. [Doc reveals the letter Marty wrote in 1955] What about all that talk about screwing up future events? The spacetime continuum?